Noncontact IC tag labels are now frequently used as recognition media in the fields, for instance, of transportation and distribution, or used for product quality control, inventory control, and various other purposes because they can record and retain information and establish noncontact communication to exchange the information with an external device.
However, when a noncontact IC tag label is used as a distribution label, it is frequently exposed to unavoidable external stress. It is fatally damaged particularly if its IC chip section receives an impact. Therefore, a structure for protecting the IC chip section was conceived in the past to avoid such a problem. However, such a structure was complicated so that noncontact IC tags could not be manufactured at a low cost.
An unavoidable structural problem of noncontact IC tag labels is that IC chips are much greater in thickness than an employed substrate and other parts. The IC chips for IC tags have been reduced in size and thickness. However, recently manufactured IC chips have a size between 0.2 mm square and 2 mm square and a thickness between approximately 100 μm and 400 μm. Therefore, when an IC chip is mounted on a substrate with an antenna pattern formed on the substrate, even if the IC chip is covered with a surface protection member and flattened, the height of the IC chip section is remarkable when the IC tag labels are stacked.
It is conceivable that IC chips may become damaged when they are stacked. When noncontact IC tag labels are to be used, several or more than a dozen of them are often stacked. For increased ease of use, labels are usually positioned so that they are oriented in the same direction. When the labels are oriented in the same direction, the IC chips are stacked vertically aligned necessarily. If, in such an instance, a heavy object is placed on top of the labels, any one of the vertically-aligned adjacent IC chips are impacted so that the IC chips, which are silicon crystals, are damaged. In this case, the labels, although they are unused, are suspected of being defective.
In a different situation where an IC tag attached to a hard article collides with a hard object, a protruding IC chip section is most likely to receive an impact.
Patent Document 1 describes a prior application filed by the applicant of the present invention and relates to a noncontact IC tag label that is formed by inserting a thin-layer structure into the area around an IC chip for IC chip protection purposes. However, the noncontact IC tag label entails an increased production cost because of the material cost of the structure and the difficulty in inserting the structure into its position.